Cooking in the JPEG Kitchen

Digital imaging is different and more convenient than film photography. The ability to select a white balance, choose a favorable ISO speed and view images on the fly are just to name a few. To put these tasty morsels in play, we’ve had to expand our horizons and elevate our learning curves. And there’s the inevitable question: JPEG or RAW?

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If you already didn’t know it, JPEG is an acronym for the Joint Photographic Experts Group who created the standards in 1986 for still image compression. JPEG specifies file format used both the codec (code-decode) that defines how an image is compressed and decompressed into an image. Your camera makes adjustments to maximize data, eliminating colors the eye can’t see and then compresses the image with a reduced color depth to save the image in the JPEG format. Because this process discards what it decides is redundant, JPEG is referred to as a lossy (not lousy) format. Keep in mind, however, that when the file is opened in a computer the lost data is, for the most part, rebuilt, especially if a low compression ratio was used.

packard.hoodUnlike JPEG, RAW requires little or no internal processing by the camera. These files contain lots more color information, providing more data but that data now requires external processing. When choosing RAW all of the data from the camera’s imaging chip is saved without any processing. Effects such as Contrast, Saturation and Sharpness are not applied to the image file. Perhaps these food analogies will help explain the difference between a RAW capture and a compressed (JPEG) capture:

  • Cake. You can purchase one ready to eat in a bakery or make one at home from scratch. The store bought cake is like the JPEG, since most choices are made for you. The bakery decides what ingredients to add in what quantity to meet their standards. JPEG photographs are processed in-camera, compressed. You take it as is. On the other hand the scratch-made cake allows you to choose the ingredients, altering them to suit your personal taste. The same thing goes for RAW images. You decide in post-production.
  • Chocolate chip cookies. Off-the-shelf brands have chips are already baked into each one, the softness of the cookie predetermined, all are uniform in size. This is clearly the JPEG version. Baked at home with almost any recipe gives you more choices: milk, dark, or white chocolate chips, the number of chips to fold into the batter, and the size of the cookies baked. It’s the RAW version.

When should you use RAW and when should you use JPEG? There are lots of discussions on this subject here and what my friend Mark Toal has written at our sister blog—Mirrorless Photo Tips. Read what we have to say and make up your own mind.

Many thanks to master photographer Barry Staver for the cooking analogies.

Author: Joe Farace

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